1. Field of the Invention
This invention relates to sheaths and introducers which are utilized in the human heart. More particularly this invention relates to a splittable sheath onto which an occlusion balloon has been secured which is utilized for the introduction of specialized medical devices into the vasculature of the heart and a process for the introduction of those devices into the vasculature of the heart utilizing the splittable occlusion balloon sheath.
2. Description of Related Art
Many medical procedures require the introduction of specialized medical devices into the human heart. For example, electrical leads, such as pacemaker leads, defibrillation leads, or leads used for cardioversion, and shunts or specialized catheters are frequently placed at specific locations in the vasculature of the heart to perform specialized cardiac procedures. Many of these medical devices, such as pacemaker leads, are very pliant and flexible. This flexibility is necessary to prevent damage, particularly to the patient""s vasculature, during the period of time those devices are present in the patient. However, because of this flexibility, it is quite difficult to advance these devices through the patient""s vasculature into the heart without the use of some stiffening element with the device. For example, one method of stiffening these medical devices is to introduce a stylet into the lumen of the medical device.
The typical procedure for introducing these devices into the heart requires passage through the patient""s vasculature. One early method of introducing such medical devices into the vasculature was to surgically cut an opening into the patient""s vasculature. However, there were several disadvantages to this procedure. To address these disadvantages, percutaneous methods have been developed to create openings in the vasculature. Once an opening is created, frequently by use of a hollow needle, a dilator is usually inserted into the vasculature which gradually increases the size of the opening. The dilator has a tapered end which spreads apart the tissue at the puncture sight as it is advanced through the vasculature. Often the dilator contains a lumen through which other medical devices may be inserted into the vasculature.
In a typical procedure for introduction of an electrode lead into the heart, a guidewire is first introduced through the vasculature into the appropriate chamber of the heart. This process is disclosed, for example, in U.S. Pat. No. 5,488,960. With the guidewire in place, a catheter/sheath or dilator/sheath combination is then passed over the guidewire and directed into the patient""s body. The catheter or dilator is then removed from the sheath. The sheath then provides a platform from which the lead may be introduced into the heart, frequently with a stylet placed within the lumen of the lead to assist in stiffening the structure of the lead and also to permit precise placement of the device within the heart.
With conventional introducers or sheaths, the maximum diameter of the pacemaker lead that can be inserted is no larger than the size of the lumen of the sheath. This limitation created a significant problem because of the nature of pacemaker leads. Frequently, the proximal end of the pacemaker lead contains an electrical connector for connection to a pulse generator. Because the size of the connecter is often larger than the diameter of the lumen of conventional cardiac introducers, splittable sheaths have been designed to assist in the insertion of these electrode leads. See, for example, U.S. Pat. Nos. 5,098,392, 4,983,168, 4,581,025, 4,451,256, 4,345,606, 4,243,050, 4,166,469 and Re 31,855. Once the splittable sheath directs the placement of the medical device, such as an electrode lead, into the correct location within the human body, it is torn apart lengthwise as it is withdrawn from the body. By being splittable, the size of the lumen of the splittable sheath can remain relatively small as it need be no larger than is necessary for passage of the distal tip of the medical device through the lumen of the sheath.
Even with these smaller diameter splittable sheaths, a problem has developed during their use. During introduction of a pacemaker lead, a significant amount of bleeding may occur at the operation site, depending upon the blood pressure present in the vessel. Once the sheath is in place within a vessel, the lumen of the sheath can provide a passageway for the free flow of blood away from the operation site. Further, because of this flow of blood, clotting may occur if the sheath remains in position for an extended period of time. These clots may cause emboli which may pass to the lung and have a detrimental impact on the patient. Splittable sheaths may also provide a passageway for the introduction of air into the heart. The inadvertent introduction of air into the blood system can cause air emboli in the patient which may also have negative effects.
Because of these problems these splittable sheaths are removed from the theater of operation as soon as possible, even if it would be preferable to maintain them in position for a longer period of time. Such hurried procedures can result in medical complications.
One method of preventing, or at least limiting, the flow of blood out of a sheath while a pacemaker lead is being introduced is for the physician to place his thumb over the exposed end of the sheath or to squeeze or pinch the exposed end of the sheath between his thumb and forefinger. However, neither of these methods for reducing the undesired flow of blood and air through the sheath is desirable, because the opportunity for loss of blood and introduction of air is still present.
Another solution to this problem is the use of a hemostasis valve secured in a splittable sheath to limit blood flow during the introduction of pacemaker leads into the heart and other similar medical procedures. However, because the exterior end of pacemaker leads is generally larger than the opening in conventional hemostasis valves, it is not possible for the pacemaker leads to pass through those conventional hemostasis valves. Accordingly, splittable hemostasis valves have been secured within splittable sheaths for the introduction of pacemaker leads, for example, in U.S. Pat. Nos. 5,755,693, 5,613,953, 5,441,504, 5,397,311, 5,312,355, and 5,125,904.
However, these valves often are difficult to split when used in a medical procedure because of the presence of fluids, particularly blood. In addition, when these valves are split, blood splattering often occurs. Further, the valve often tears unevenly, making it more difficult to remove the splittable sheath and the splittable valve from the operating theater. Further, some physicians are hesitant to force the tines of leads for pacemakers through these valves because they fear damage to the tines. In addition, some physicians may want to delay the introduction of a hemostasis valve into the sheath even after the sheath is already in position within the patient. To solve these problems, an improved partitioned hemostasis valve system can be utilized, which is disclosed in Ser. No. 09/207,295, filed Dec. 8, 1998 and owned by the assignee, the contents of which are incorporated herein by reference.
Many specialized medical devices are utilized in the vasculature of the heart, specifically in the coronary sinus. The coronary sinus is the largest cardiac vein in the heart and serves as a venous conduit from smaller veins within the myocardium to the right atrium. A tissue fold or primitive valve covers the coronary sinus ostium to prevent blood from backflowing into the coronary sinus as it is being pumped out of the right atrium. Located within the right atrium, generally, above the coronary sinus is an oval depression called the fossa ovalis. Between the inferior vena cava and the coronary sinus ostium is the eustaclan ridge. The location of each of these elements may vary from patient to patient.
The coronary sinus is often used for electrophysiological procedures in the heart, including both diagnostic and treatment procedures. The coronary sinus can also be used for pacing both the left and right sides of the heart. Gaining access to the ostium of the coronary sinus, however, is often a difficult procedure, especially because of the large number of similar anatomical structures located near the coronary sinus within the right atrium. It is especially difficult because these anatomical structures do not show up on a fluoroscope.
Current medical procedures available for introduction of devices such as pacemakers, implantable defibrillators, specialized catheters or devices used for cardioversion or cardioplegia into the coronary sinus are frequently time consuming and difficult. To address these concerns, particular types of diagnostic catheters have been designed as disclosed in U.S. Pat. Nos. 5,423,772, 5,549,581, 5,643,321, and 5,722,963. These patents disclose precurved, coronary sinus catheters, which because of their unique curvature, can be advanced through the patient""s vasculature directly into the coronary sinus, where it can be used to perform diagnostic and treatment procedures. U.S. Pat. No. 5,488,960 discloses a different type of device designed for use in the coronary sinus.
One common medical procedure that utilizes a medical device introduced within the coronary sinus is cardioplegia. This procedure is commonly used during heart surgery, and requires the introduction of a cardioplegia solution into the coronary sinus. While numerous cardioplegia catheters have been designed, it has been discovered that medical devices introduced in the coronary sinus can be easily ejected because the coronary sinus walls are slippery, extensible, and tapered so that the coronary sinus vessel becomes smaller in the direction in which the medical device is advanced into the coronary sinus vessel. In order to overcome these problems, occlusion balloons have commonly been secured near the distal end of the cardioplegia catheter. To prevent dislodgement of these occlusion balloon catheters after introduction into the coronary sinus, the outside surface of the occlusion balloon is coated or modified with physical extensions which frictionally engage the coronary sinus and thus provide a higher retentive force for the medical device in the coronary sinus than is present in conventional occlusion balloon surfaces. Typical devices that can be used for this type of medical procedure are disclosed in U.S. Pat. Nos. 4,648,384, 4,927,412, 5,129,394, 5,720,726, and 5,807,326. In addition to the occlusion of the coronary sinus, U.S. Pat. No. 5,814,016 discloses medical devices for occlusion of other vasculature associated with the heart, particularly the aorta, utilizing either concentric or eccentric-shaped occlusion balloons.
While these occlusion balloons secured to conventional cannula have been useful for cardioplegia and certain other types of coronary procedures, there is still a need for devices which assist in the placement of pacemaker electrodes in the coronary sinus. Further, once these pacemaker electrodes are in place, methods must be utilized to remove the supporting medical devices from the heart without dislodging the electrode leads.
Accordingly, it is an aspect of this invention to disclose a device which assists in the efficient placement of medical devices, particularly small, flexible medical devices, such as electrode leads, into the coronary sinus.
It is a still further aspect of the invention to disclose a splittable sheath on which an occlusion balloon has been secured, which assists in the introduction of medical devices into the coronary sinus.
It is a still further aspect of this invention to disclose a fixed shape splittable sheath onto which an occlusion balloon has been secured to assist in the introduction of medical devices into the coronary sinus.
It is another aspect of the invention to disclose a fixed shape splittable occlusion balloon sheath that can be utilized with a fixed shape dilator for placement of small, medical devices into the coronary sinus.
It is a still further aspect of the invention to disclose a splittable occlusion balloon sheath which contains a splittable hemostasis valve, preferably a partitioned hemostasis valve system for introduction of medical devices into the coronary sinus.
It is a still further aspect of the invention to disclose a splittable occlusion balloon sheath for introduction of small medical devices into the coronary sinus, wherein the balloon is constructed such that the distal tip of the occlusion sheath is centered within the coronary sinus when the occlusion balloon is inflated.
It is a still further aspect of the invention to disclose a splittable occlusion balloon sheath for introduction of small medical devices into the coronary sinus, wherein the occlusion balloon contains a system to enhance frictional contact of the occlusion balloon with the coronary sinus to assist in its retention within the coronary sinus throughout the medical procedure.
These and other aspects of the invention are obtained from the various designs of the device of the present invention, and by the processes disclosed herein.
The present invention relates to a splittable occlusion balloon sheath comprising an occlusion balloon secured near a distal end of a splittable sheath, utilized to introduce a medical device, such as a pacemaker lead, defibrillator lead, or diagnostic or treatment device, into the coronary sinus of the heart. After utilization, this splittable occlusion balloon sheath can be split into two (2) separate sections, and removed from the operating theater.
The present invention also relates to a splittable occlusion balloon sheath with a predetermined shape, which assists in its placement into the coronary sinus.
The present invention also relates to a splittable occlusion balloon sheath, which contains a hemostasis valve within a lumen of the splittable occlusion balloon sheath, to prevent the backflow of blood through the sheath during a medical procedure. Preferably, the hemostasis valve is also splittable. More preferably, the hemostasis valve is contained within a partitioned hemostasis valve system and includes an adaptor for securing the system to the splittable occlusion balloon sheath.
The invention also encompasses a splittable occlusion balloon sheath system for the introduction of medical devices into the coronary sinus of the human heart, which includes a splittable occlusion balloon sheath and a dilator advanced through a lumen of the sheath. Preferably, the dilator and/or the splittable sheath are formed in predetermined, precurved shapes.
The splittable occlusion balloon sheath is not limited to introducing leads into the coronary sinus. The invention also encompasses a splittable occlusion balloon sheath useful for introducing other small medical devices into the vasculature of the heart, such as electrophysiological diagnostic devices and devices useful for sensing and ablation procedures.